Northern's Sterlingsilber M52 Turbo 325is

[Northern]

I've been hearing about Arduino for a long time now, and assumed it was some crazy shit that wizards used, so I never paid any attention. Recently I was talking to my friend at one of the other universities in the city, and they were building a robot that used arduino with a colour sensor to sort blocks.

For whatever reason, I googled "arduino boost controller" and found a decent amount of info. I've wanted a Turbosmart Eboost 2 for a long time since it has all the bells and whistles, but I don't have $700 to spend on a boost controller.

Long story short, I ordered an Arduino starter kit for my kid brother for xmas. I really think he'd be into this sort of stuff, so we'll start off with goofy stuff, then maybe we'll make a boost controller of some sort.

I'm thinking:
Arduino unit
Map sensor
VW N75 solenoid (or MAC, not sure)
digital screen
alarm/buzzer

random connectors, probably off spare harnesses I already own.

Goals:

1: Control the wastegate
2: Show boost pressure on a small screen, mounting location TBD.
3: Output a 0-5v signal to log MAP through unused input on MS41/OBD2 (ba114 has a post about this)
4: Audible alarm for overboost, set somewhat conservatively in the hopes it will be useful.
5: (future version) Set boost level up/down with buttons.
6: (future version) Boost by gear. No sweet clue how to implement, thinking of somehow mapping out RPM vs VSS curve for first/second gear, then running a check to determine if first/second/other and setting a different target boost for each scenario.


Implementation:
loop:
read map
if(map < target , solenoid fully closed
if(map >= target , solenoid fully open
if(map > target , solenoid fully open + audible alarm.
set ECU MAP output to x voltage.

Going to need some tweaks on what range is acceptable for "target" and how to taper as it approaches the target. Obviously if I keep the WG shut until the instant I hit full boost, I'm going to overshoot the target by a good amount...

Maybe implement a second circuit for a solenoid on the BOV line that closes (or vents to atm?) in case of overboost? Not sure why I'm so worried about this. Maybe I should just make sure my WG is doing it's job, and secure the line.


Arduino apparently does PWM with +5v, not ground (like MS would, for example), and not 12v that the valve needs. I assume I can get around this by using a relay.

[varg]

The 5v PWM signal from the arduino is a good thing actually, use it to drive an N-channel MOSFET.

Also
P I D
Can't help you with code or Arduino. I don't like coding and have never messed with an Arduino.

[Northern]

The 5v PWM signal from the arduino is a good thing actually, use it to drive an N-channel MOSFET.

Also
P I D
Can't help you with code or Arduino. I don't like coding and have never messed with an Arduino.

The N-Channel MOSFET sounds like a better idea than trying to trigger a relay. I think I see how I can go about using one to switch the ground

Ok, so I sort of get what PID is now after a quick google, and it sounds like exactly what I need. Not sure how to go about that, or open/closed loop for it, but there appears to be lots of info out there for PID with arduino.

Not sure how programming it works. I think it plugs into a laptop and there's a program that flashes it onto the chip.
I don't know what language it uses, but it seems like it uses it's own compiler and is a dumbed down version of C/C++ with its own predefined functions.

[Northern]

More Arduino boost controller rambling:


Ordered a handful of arduino UNO boards for like $4ea. Probably will try to upgrade to something a lot smaller later if this works out.

I'm torn between a 3bar GM MAP sensor or something like a MPX4250AP. Not really sure of pros/cons, price is similar.

Either 16x2 or 20x4 serial display to see settings or something.

up/down buttons for selecting/changing target boost or whatever settings.

N75 solenoid

n-channel MOSFET (that I guess will be free hanging?) inline resistor to a PWM capable output on the Arduino board.

Get 5v power from an old car USB charger.


That's all for the basic boost control stuff... Other:

• VSS input
• RPM input -> Together could plot rpm vs wheelspeed to do some sort of boost by gear
• Take Wideband output from the LC-1 to use somehow. Maybe open solenoid if it goes lean, just how to define lean when cruise/coast will be even leaner...
• Spit out wideband 0-5v signal to DME for logging
• Spit out MAP 0-5v signal to DME for logging

I've found a few codes to look at, nothing specifically what I want, but seems easy enough to reverse engineer it and get somewhere.
Arduino stuff seems weird vs C, I'm mostly trying to wrap my head around the setup

[Northern]

Alright, back to business:

I'm busy with school, it's cold/wet outside, and I have no money.

There, now that the excuses are out of the way, here's what I am doing:

1. My sunroof is rotten, and apparently all the other ones around here are too, so I bought one from the Southern US which looks perfect besides being the wrong colour. I'll probably pony up for some new sunroof seals, paint it, and slap it in this spring so I can open my sunroof without going blind.

2. I'd love to do the track school in the spring (pending money/car working/tuned) but I don't think the Z3m rad is enough to keep the heat away. I meant to buy an S54 housing forever ago, but I finally did it now. I also purchased the oil line adapter.

Once that gets here, I need to figure out where the oil cooler is going to go and measure for size. Probably somewhere near the stock location, bolted to the bottom of the rad support (there's only 2-3" above the FMIC)

Not sure what to get for an oil cooler, so I'm open to suggestions. I know people running the cheap ebay ones without issues, and they seem decently large... but I'd rather have fittings on the end, not the top.

[AWDBOB]

I've used these in the past (not on e30s) with great success. If it were me, there is no way I'd consider an oil cooler from ebay. If it fails and you're in boost.......

http://www.jegs.com/i/B%26M/130/70273/10002/-1?CAWELAID=1710681893&CAGPSPN=pla&CAAGID=15769068431&CATCI=pla-217780705991&gclid=CNKv66vL3tECFc63wAodMZ8FyA

[Northern]

I was looking at something like the Derale cooler that Sh3rpak!ng has for his PS: Similar shape to stock M20, but with in/out on the same end and AN fittings. This seems like it would be the easiest one to fit by far.

Unfortunately I think they only come as PS coolers with -6AN fittings, so I'm going to have to get creative I guess.

[Northern]

Here's a refresher for how much space I have above/below the fmic... not much.

[Northern]

Setrab makes some nice slim ones that would fit... for $400USD

Maybe it isn't worth trying to fit one there... I could cut the valence/bumper some more for airflow and stuff a generic shaped one in front of the driver's wheelwell above the brake duct(which I want to retain)

[varg]

If you place it horizontally behind the valance/lip you could make an air duct to feed it from the bottom oval vent.

I'm currently running without an oil cooler because there just is not a lot of real estate for one with a big FMIC, this would not be an option if I intended on tracking the car, but I have neither time nor money for that so no big deal.

[Northern]

So I've stumbled across FC RX7 coolers, which are like a larger version of the M20 one, 500x100x50mm core... I think 605x110x52 overall dimensions. Feed/return on same side.

Biggest problem is finding one that's not made in china.

Alternatively, use the M20 cooler. Or pretend it's a Porsche and jam a normal shaped one in the wheel well with creative ducting/stone guard.

[jph]

Northern's S257 + M52 325is

Here's a quick shot of the oil cooler I'm going to run on my E30 with a turbo M52. I have a new S54 oil filter housing and VAC AN adapter for the ports on the housing. Car is in paint now so haven't had a chance to hook it all up. I'm using the low profile Setrab fittings on the cooler itself and it juuuuust clears the underside of the top of the core support.

EDIT: It's a Setrab Series 9 Oil Cooler, 15 Row, M22 Ports




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[ak-]

^ That's exactly how I have mine - behind the kidneys.
We also welded 45's to my intercooler for a precise fit to insure I can run fogs and brake ducting. Yours looks nice. :p

[jph]

^ That's exactly how I have mine - behind the kidneys.
We also welded 45's to my intercooler for a precise fit to insure I can run fogs and brake ducting. Yours looks nice. :p

Thanks man. I might look into getting some extensions/angles welded on to my IC once I get the car back, put the engine in, and mock up the charge piping. As it sits right now I had to shave a lot off the back of the brake duct inlets on my MT2 valance to get them to clear the elbows and even then they still make contact but it's slight. I mean I pretty much shaved the ducts down to the back of the valance. Looks a little funny but it works.


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[ak-]

Sweet - as long as long term they don't cut any silicone that's dandy.
The convenient thing about the welded 45's, besides precise routing, is that the t-bolt clamps are much more accessible with the turn of a wheel now.

Couple of pics, one with the oil cooler like yours. I ran my oil lines under the unit because I think the AC stuff was in the way iirc.